The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
1. Field Of The Invention
The present invention relates to the launching of projectiles and more particularly, to a detachable shock-absorbing ram-plate used to absorb the shock caused by launching impact forces.
2. Description Of The Prior Art
Launchers are used to launch projectiles, such as torpedoes, missiles, countermeasures, and other underwater devices. Ram-plates can be used to protect the projectile from the charge explosion and to prevent blow-by of launch fluids during launch. Currently, ram-plates used for such launchers are made of solid metal and are designed to transmit forces rigidly rather than mitigate those forces. For certain launching systems, the projectiles experience a large initial launch impulse that requires the projectiles to be designed to very high standards to avoid damage.
Also, the existing ram-plates are not attached to the projectiles. As a result, spring like dynamics during some launches may cause the ram-plate to separate from the projectile and then re-strike the projectile once the propulsive launch force recovers. Such ram-plate re-strike has potential to damage some projectiles.
Accordingly, one object of the present invention is to reduce shock to the projectile using a shock-absorbing ram-plate without requiring significant modification of the propulsive launch mechanism.
Another object of the present invention is to prevent damage to the projectile due to ram-plate re-strike during launch by preventing separation of the ram-plate from the projectile during launch dynamics.
The present invention features a projectile launching system comprising a launch tube, a projectile disposed in the launch tube, a shock-absorbing ram-plate, and a break-away fastener removably fastening the shock-absorbing ram-plate to the projectile. The shock-absorbing ram-plate compresses to absorb impact forces caused by launching. The break-away fastener has strength sufficient to withstand the impact forces but insufficient to prevent detachment of the shock-absorbing ram-plate proximate an end of the launching tube at the end of the launch. The break-away fastener can include a snap, a pin, a screw, a bolt, a cable, or the like. The launch tube includes a stopping structure for stopping the shock-absorbing ram-plate proximate the end of the launch tube such that the break-away fastener fails causing the shock-absorbing ram-plate to remain in the launch tube while the projectile is launched.
The present invention also features a single-impact viscous fluid ram-plate comprising a cylinder defining a cavity and a piston positioned within the cavity of the cylinder. The piston includes at least one aperture extending therethrough. A viscous fluid is disposed in the cavity between the cylinder and the piston. The viscous fluid is forced out of the aperture in the piston when an initial impact force acts on the piston such that the piston and the cylinder are compressed.
In another embodiment, the detachable shock-absorbing ram-plate includes a piece of elastic material. In a further embodiment, the detachable shock-absorbing ram-plate includes a cylinder defining a cavity, a piston positioned within the cavity of the cylinder, and a gas disposed in the cavity between the cylinder and the piston. The piston compresses the gas upon receiving launching impact forces.